Pocket-calculator.



G. SMALL.

POCKET CALCULATOR.

APPLICATION FILED FEB-17,1913

Patented Feb. 12, 1918 117 Van for.

GILBERT SMALL. OF WALTI-IAM, MASSACHUSETTS.

POCKET-CALCULATOR.

Specification of Letters Patent.

Patented Feb. 12, 1918.

Application filed February 17, 1913. Serial No. 748,805.

To all whom it may concern:

Be it known that I, GILBERT SMALL, a citizen of the United States, andresident of Valtham, in the county of Middlesex and State ofMassachusetts, have invented certain new and useful Improvements inPocket- Calculators, of which the following is a specification.

This invention relates to calculators in the nature of cylindrical orcircular slide rules in which there are complemental scales mounted uponthe peripheral or outer cylindrical surfaces of two circular orcylindrical bodies which are connected together with capability ofrelative rotary movement about their common axis. The objects of myinvention are: first, to provide a runner or index associated with suchmembers so as to be constrained to move about the common axis thereof inproximity to the cylindrical scales thereon, to be used as an index inconnection with such scales; second, to provide in connection with acalculator of the character indicated, one or more additional computingscales on one or both of the end faces of the calculator, such scalesbeing provided with radial graduations; third, to construct the runneror index member with a pointer or pointers or other index marks arrangedin proximity to such additional scale or scales and having a definiterelation with each other and with the index which cooperates with thecylindrical scales to the end that the additional or end face scales maybe used in conjunction with the c lindrical or peripheral face scales;and ourth, to make the runner or index member of such shape andconstruction that it embraces the ends of the calculator and is soshaped and guided in respect to its motion, that it shall not interferewith the thumb and fingers of the user when holding and operating thecalculator. I

.T he fore oing and other objects are carried into e ect by thedevice'illustrated in the accompanying drawings and described in detailin the followin specification, which device embodies that form of myinventionwhich at the present time I prefer to other possible forms.

In the drawings,

Figure 1 is a plan view of the cylindrical calculator with the runner orindex member attached. I

Fig. 2 is a front elevation of the same as viewed from the under side ofFig.1.

'tate.

Fig. 3 is a cross section on the center line 33 of Fig. 1.

Fig. 4 is a detail section on a plane perpendicular to the axis throughthe runner and a part of the calculator.

The same reference characters indicate the same or similar parts in allthe figures.

Referring to the drawings A and A represent the relatively movableelements or members of the calculator, the member A being a disk and themember A an annulus which is connected to the member A by a couplingdisk B. The latter is connected to the disk A by any convenient meanssuch as screws or the like C and has a peripheral flange B overlappin alip A of the mem ber A, thereby provi ing a bearing on which the memberA may turn and a lock to hold the member A close to the member A andprovide sufficient friction so that such members will not turn toofreely relatively to one another. Preferably the members A and A areprovided with knurled ribs or lips D and E, respectively, to assist inmanipulation.

On the peripheries, that is, the adjacent cylindrical external faces orsurfaces of the members A and A are scales P and P, respectively, suchsurfaces and scales bein of the same diameter so that the adjacent e gesof the scales meet and their graduations may be set in registry. Saidscales are graduated in any desired values, conveniently in some suchmanner as the well known slide rules commonly used.

As thus far described, my calculator is not essentially different fromothers which have already been produced, specifically that shown in thepatent to Roger W. Conant, No. 657 ,916 dated September 18, 1900, and Imake no claim to any of the features hereinbefore described.

The first feature of my invention relatesto arider or runner. R, whichis mounted upon the calculator so as to cross the peripheral orcylindrical face thereof and travel near the scales P and P about theaxis of the'calculator, which is the same axis about which the members Aand A relatively r0- T his rider or runner also embrace the ends or endfaces of'the calculator as shown and is provided with arms, on theendsof which are inwardly turned flanges R" which entergrooves O and O,concentricwith the axis of the calculator, in the hubor bearing disk. 13and the member A, respectively. The design of my calculator has beenchanged from that of the calculator shown in the patent above noted bymaking the cen tral hub or hearing disk B sufliciently large to provideroom for the groove 0 and to have such groove located so far from theaxis of the calculator that the runner may rotate freely withoutinterfering with the thumb or fingers of the user, when grasping thecalculator near the axis.

The portion of the rider or runner which extends across the scales P andP is provided with an index H which may be made of any practicablecharacter, but is preferably a scratch or line on the inner face of atransparent window or pane G carried by the rider. In the constructionillustrated that part of the rider which crosses the periphery of thecalculator has an opening, and a piece of transparent material, such ascelluloid or glass, is placed across that openin and is secured by lugsR formed on the ri er and bent over the ends of the transparent piece G,as shown best in Fig. 4. Preferably the transparent piece is placedbetween the rider and the scales, and the index mark is applied to theface of the transparent piece nearest to the scales, so as to be closeto the scales and avoid errors due to parallax when reading the scalewith respect to the index. This index mark is also parallel to the axisof the calculator.

On the side or end face of the member A is a scale S and on the face ofthe member A-, which is the opposite end face of the calculator, is ascale S these scales being provided with radial graduations representingany selected mathematical values, one of them being partially shown inFig. 1. Those parts of the rider which extend over scales S and S areprovided with openings R through which the scales may be observed, andat the edges of these openings are pointers or index elements H. In theembodiment of the invention shown I have made these index elements aspointed projections, but I do not intend to limit the invention to indexelements of this particular character, as I contemplate forming indexelements for coeperating with the scales S and S in the same manner thatthe index mark H is made, that is, as a scratch or line on a transparentpiece overlying the opening R The graduations of the scales S, S, P andP bear a definite relation to one another, and so do the index elementsH and H of the rider, this relation being 'such that the index marks maybe used in reading from the scales P and P to the scales S and S or thereverse, and from the scale S over to the scale S. That is, the indexmarks are so arranged that the graduations upon the several scalesadjacent to such marks in any position of the rider representintelligible values.

I have already indicated that it is important that the rider shall be somounted as to leave clear the space for the thumb and fingers of theuser by which the calculator is held at its center, and I have shown howthis important effect is secured. It is also important that there be theright amount of friction between the rider and the main member A of theinstrument,

and sufiioient clearance between the riderand the annular member A, sothat when such annular member is rotated, the runner will remain for thetime being a part of the larger main member, and so also that the riderwill not slide around the instrument except when pushed by the fingersof the operator. The ends of the rider are in contact with the member Aand the hub B, which are in effect one piece, and by so constructing therider that it clears the annular member A, the desired effects aboveindicated are secured. The desired friction may be obtained by makingthe rider of one piece of sheet metal, as shown, and depending upon thespring of the metal to grasp the opposite sides of the instrument withsufficient pressure, but it is within my contemplation to provideadditional frictional devices. So far as I am aware no calculatingdevice has heretofore been devised in which there are continuous scalesin combination with an index member capable of being completel rotatedwithout mtcrference with the ngers by which the calculator is grasped,or in which there is an index member capable of being used for readingfrom a cylindrical peripheral scale to a circular scale on the end faceof the instrument or an index member embracing the periphery for readingfrom a scale on one end face to a scale on the opposite end face of theinstrument. My invention supplies the features lacking in previouscalculating devices and furnlshes an attachment by which great gains aremade in accuracy of reading the instrument and in case and convenienceof its use.

What I claim and desire to secure by Letters Patent is:

l. A calculator comprising complemental cylindrical members pivoted sideby side on the same axis, each having a cylindrically arranged scale onits periphery, and

a circularly arranged scale on its face, and

relate as to permit readin about the axis of the calculator and havingcorrelated indices adjacent to the respective scales.

3. A substantially cylindrical calculator comprising two coaxial membershavin contiguous scales on then: perlpheries, an one of said membershaving a scale on its end, and a rider connected with said calculatorand constrained thereby to move in a circular path concentric with thecalculator, said rider having openings over the several scales rovidedwith index elements and so from one scale to another, one of such in exelements being a transparent pane extending across one of such openingsand provided with a line. 4. A calculator comprising two coaxiallyarranged contiguous relatively rotatable cylindrical members, equal indiameter, having scales on their peripheral faces, and also having planefaces perpendicular to their common axisand scales on said plane faces,and an index crossing said scales and being mounted to rotate about theaxis of the calculator, the index also extending over both end faces andthe scales thereof of the calculator and bearing irictionally againstthe same.

5. A calculator com rising two substantially cylindrical mem ers mountedcoaxi-' ally with provision for rotation of one relasaid rider havingopenings over the several scales provided with index elements so relatedas to permit reading correlated values from one o the scales to another.

In testimony whereof I have afiixed my signature, in presence of twowitnesses.

. GILBERT SMALL. Witnesses:

ART UR H. BROWN, P. W. PEZZETTI.

